IR 05000331/1993018

Insp Rept 50-331/93-18 on 931025-1105.No Violations Noted. Major Areas Inspected:Sws Operational Performance Insp

ML20058M733
Person / Time
Site:	Duane Arnold
Issue date:	12/14/1993
From:	Westberg R, Wright G NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION III)
To:
Shared Package
ML20058M726	List: IR 05000331/1993018 ML20058M722
References
50-331-93-18, NUDOCS 9312210089
Download: ML20058M733 (20)

Text

. _ _ _ _ _ _ _ _ _ - _ _ _ _ _ _ _

, .

.

.

U. S. NUCLEAR REGULATORY COMMISSION REGION Ill Report No. 50-331/93018(DRS)

Docket No. 50-331 License No. DPR-49 Licensee: Iowa Electric Light and Power Company IE Towers P. O. Box 351 Cedar Rapids, IA 52406 Facility Name: Duane Arnold Energy Center inspection At: Duane Arnold site, Palo, IA

Inspection Conducted: October 25 through November 5, 1993 j

Inspection Team: R. Westberg, Team Leader i

.R. Doornbos, Licensing Exad ner J. Gavula, Reactor Inspector J. Neisler, Reactor inspec: r NRC :onsultant: T. DelGaizo, Main Line Eng- eering Associates ap; :ced By: bhhk -WM ".

P3Tf Mestberg, Team Lea"e r G k 9 l13 Date l Region III

'

Ap;rced By: NO h bwE'nT f"'

Geoff rey C. Wright, Chief

Date

Engineering Branch Ins::c. tion Summary intrection on October 25 - November 5,1993 I:ecort No. 50-331/93018(DRS)).

Red :ed scope SWS operational performance inr:e:ti:n (SWSOPI) in accordance wi: ';RC Temporary Instruction 2515/11 Ren-ts: The team determined that the SWS design and operation were sat' Hattor The team identified the follce g program strengths:

• experienced and technically competent e ;ineering staff, l * plant material condition, e incorporation of SWS changes inte the  :+-ai;r training progra .

'ng:

~

- ;i:: :1 u ' u n b e E n q i r= e r i ra : . ;1s pc ar i

?!; -

a M e q e;c 1r v t,m 3 ;; ,

9312210089 931215

'

PDR ADOCK 05000331-G ppg ._

.. ..

_ _ _ _ - _ _ -

.

.

.

!

The team also identified the following weaknesses: l

• lack of implementation of heat exchanger performance monitoring program,

• incorrect computer modeling of SWS components in the simulator and, !

e lack of testing of check valves which isolate well water from ESW at the control room chiller One violation and three unresolved items were close One unresolved item was !

identified relative to a well water line that was not reviewed under the original IEB 79-14 program (Section 5.4).  !

!

t P

I l

l i

!

'

.

!

.

!

,

.

f i

,

,

_ _

.. . . . . . - -

. .

,

TABLE OF CONTENTS Page i

EXECUTIVE SUMMARY....................................... ......... i ; INSPECTION SCOPE AND 0BJECTIVES............................. 1 , LICENSEE ACTION ON PREVIOUS INSPECTION FINDINGS............. 1 .; GENERIC LETTER 89-13 IMPLEMENTATION......................... 2 ,

. SYSTEM DESCRIFTI0N............................... .......... 2

MECHANICAL DESIGN REVIEW.................................... 3 PERATIONS.................................... ............. 6 MAINTENANCE. ....... . ....... ............... ............. 7 SURVEILLANCE AND TESTING... ............ ........... . .. 9 UNRESOLVED ITEMS . ........ . .. ............... .. .. 9 ,

10.0 EXIT MEETING. .. . .. .... . . . . ........ . . ... 10 !

>

'

Appendix A - Personnel Contacted Appendix B - Generic Letter 89-13 Action Items  !

.

t

+

a f

e i

!

r

!

[

$

.

b

'

&

I b

w + ,- - .,, . ,--s .-. , , ,p..y

- - -. - - _ . . . . .

. .

.

Executive Summary During the period October 25 through November 5, 1993, a Region III inspection team conducted a SWSOPI at the Duane Arnold Energy Center. The SWS included safety related containment fan coolers, spent fuel pool heat exchangers, battery room coolers, and the diesel generator coolers. For these systems, the inspection included a focused mechanical design review; system walkdowns;

'

review of system operation, maintenance, and surveillance; assessment of GL *

89-13. " Service Water System Problems Affecting Safety Related Equipment," i quality verification and corrective actions guidelines; and system .

unavailabilit l The team considered Duane Arnold's SWS capable of performing its safety j function and design and operation was satisfactory. Tne team identified some strengths in the program. For example: ,

• experienced and technically competent mechanical engineering staff,

• good plant material condition,  ;

incorporation of SWS changes into the operator training progra * simulator use by Engineering to evaluate SWS changes prior to implementation and, e good SWS sel f-assessmen '

The team also identified the following weaknesses:

1ack of implementation of heat exchanger performance monitoring program, e incorrect computer modeling of SWS components in the simulator,

• iack of testing for the check valves which isolate weil water from ESW ,

'

at the control room chiller ,

i t

!

l I

i

!

- . - _

_ . .- . . . . - . . . - - ._ .-, .

!

!

DETAILS  !

!

i Inspection Scope and Ob_iectives  !

!

Numerous problems identified at various operating plants in the country have called into question the SWSs' ability to perform their design functio i These problems have included: inadequate heat removal capability, biofouling, i silting,- single failure concerns, erosion, corrosion, insufficient original 'j design margin, lapses in configuration control or improper 10 CFR 50.59 safety i evaluations, and inadequate testing. NRC management concluded that an in-  ;

depth examination of SWSs was warranted based on the identified deficiencie !

The team focused on the SWS's mechanical design, operational control, maintenance, and surveillance. The team also evaluated aspects of quality I assurance and corrective action programs related to the SWS. The inspection's  !

primary objectives were to: 1 l

assess SWS performance through an in-depth review of mechanical systems i functional design and thermal-hydraulic performance; operating,  !

maintenance, and surveillance procedures and their implementation; and i operator training on the SWS,

!

t

• verify that the SWS's functional designs and operational controls are  ;

capable of meeting the thermal and hydraulic performance requirements

'

and that SWS components are operated in a manner consistent with their i design bases,

assess the licensee's planned and completed actions in response to  ;

Generic Letter 89-13, " Service Water System problems Affecting Safety  !

Related Equipment," July 1989, and  !

l

assess SWS unavailability resulting from planned maintenance, .

surveillance, and component failure !

. ,

The areas reviewed and the concerns identifiec are described in Sections througn 8.0 of this report. Conclusions are provided after each sectio ,

!

Personnel contacted and those who attended the exit meeting on November 5, 1993. are identified in Appendix Details pertaining to GL 89-13 action t items are attached as Appendix .0 Licensee Action on Previous Inspection Findings  ; Closed)_ Violation 50-331190003-01: Multiple examples of design control *

deficiencies in piping and pipe. support calculation The- icensee's response, dated June 29, 1990, provided corrective actions to address all of the relevant issues. In additicn to the specific deficiencies notc: curing the inspection, the licensee perf o ed a comprehensive review lof all e a sting seismic calculations and found 2 - Der of others'inilar

-

Nf- =m n Mough am imately 30 pir rc 20 pipa suppe-t

_ . .. -.

__ . _ _ _ _ _ -_ _ _ . _ .. _ _

. i

!

.

r calculations required revisions or reanalysis, there were no instances where discrepancies resulted in field modifications. The team reviewed selected

,

calculations and did not identify any concerns with corrective action adequacy. This item was considered close * Closed) Unresolved Item 50-331/90003-05: Pipe support HBD-25-H63 i incorrectly modeled in analysis No. 80-32 The licensee revised the piping analysis with the correct support direction  !

and confirmed that stresses were still within allowable limits. The team reviewed the analysis, determined that it was adequate, and considered this  :

item closed.

p (Closed) Unresolved Item 50-331/90003-06: Pipe support analyses for HBD-24-H13, HBD-24-H15 and HBD-25-SG145 did not evaluate as-built configurations,

,

t The licensee revised the analyses with the appropriate as-built information and confirmed that all three supports were adequate. The team reviewed the analysis, determined that it was adequate, and considered this item close ,

i f {Cl_osed) Unr_esolved Item 50-331190003-07: Pipe support analyses for r

HBD-25-FH69 and HBD-25-H16 did not evaluate all loads applied by the l'

associated piping syste The licensee revised the analyses with the appropriate loads and confirmed that they were adequate. The team reviewed the analyses, determined that they i were adequate. and considered this item close t Generic letter 89-13 Implementation

'

The NRC issued GL 89-13, " Service Water System Problems Affecting Safety Related Equipment," requesting that licensees take certain actions related to l l their SWS. These actions included establishing the :ppropriate frequencies-

!

for testing and inspecting safety related heat exchangers over three operating '

cycles, to ensure the operability of SWSs that are credited for cooling safety '

related equipmen I The team found Duane Arnold's inplementation of GL 89-13 commitments to be acceptable; however, some additional actions are required to achieve full  ;

impl e r.entati o The team noted that -several of these actions are schedu.ied for completion in the first half of 199 {

The team found the proposed  :

sche:ule acceptable, provided the dates are firm and are not allowed to slip {

be r d the time frames indicated. Details pertaining to each GL 89-13 action  ;

ite are contained in Appendix B of this repor !

'.0 Sn tem Desc_ription '

Tr.e SWS is comprised of three separate safety related cooling water systems; f e er;ency service water (ESW). residual heat removal service water (RHRSW),

7: *

.er watn s uopl y (RWS). ESW arovin cooli n ; various esetin'

,

,

~ such r +he emerge cy die- ^ gener v (E;; control r & cr, '- :r:,

{

>  ;

'

!

!

l n

t

~5

- _ = _ . - .

,

- i

and various emergency core cooling system (ECCS) component RHRSW cools the +

RHR heat exchangers, in both shutdown cooling and torus cooling. RWS supplies river water to the ESW and RHRSW pump pit !

The ESW system consists of two independent trains, each containing a single i 100% capacity pump, capable of being cross-tied by manual spool-piece connection. Each loop cools one EDG, one control building chiller, ECCS pump room coolers, ECCS pump bearing and seal coolers, RHRSW pump bearing coolers, -

and HVAC instrument air compressors. The ESW system is shut down during :

normal plant operation and starts automatically on a loss of off-site power

"

signal. Control building chillers, which operate at all times, are normally i'

cooled by the nonsafety related well water system. When necessary, well water is isolated from ESW by check valves or operator controlled motor actuated valve RHRSW consists of two independent loops, each with a 100% capacity RHR heat

.

exchanger and two 50% capacity pumps. The system does not normally operate and is manually started for shutdown cooling or torus cooling. System flow rate is either automatically or manually controlled to assure RHRSW pressure remains at least 20 psi above RHR system pressure to preclude heat exchanger '

tube leakage from being discharged with the service wate Water supply for both the ESW and RHRSW systems is provided by RW RWS consists of two separate loops, each with two 100% capacity pumps which transfer water from the Cedar-River intake structure to the circulatine water i pump house stilling basin, which is directly connected to the ESW/RHRSW pump ;

pit One of four RWS pumps runs during normal operation to provide ccoling j tower make-up, with flow automatically controlled based upon cooling tow basin level. Under accident conditions, one RWS pump in each loop starts

,

automatically and level control valves fail full open to assure water to the ;

pump pits is not restricte !

L

1. Mechanical Design Review -

!

The mechanical design review involved a determination of SWS design bases and !

design configuration by review of calculations, analyses, preoperational !

tests, performance tests, alarm response procedures, recent modifications. and normal and abnormal operating procedures. Since a large number'of calculations and test procedures had been prepared following the NRC's 1990 {

!'

service water SSFI, the team focused its design review on these documem The team concluded that service water mechanical design was adequate and that l sufficient flow would be provided to safety related heat exchangers un:e- !

cesign basis events, including the most limiting single active failure. The ;

team also noted that substantial improvements had been made in cesign '

documentation, administrative controls, and testing and monitoring proce res since the 1990 NRC SSFI. However, the team was concerned about the large number of action items, with completion due dates throughout 199*., resC f ng ,

from the recent self-initiated service water operational performce i n s pec t i on.. ine team considered timely completion of many of these itrs

,

t-Mial to c;nt .ded SWS reliabilit y, i

f

. . _- .

~

_ _ _ _

.

. Heat Exchanger Performance and Trendina Proaram While a framework for heat exchanger performance trending has been established at DAEC and a number of initial tests have been performed, the team was concerned that several specific items need to be completed to fully implement the program. For example:

• The procedure to monitor control building chillers has not been approved and performed. An inspection and cleaning frequency for these coolers has not been establishe l

• Procedures have not been written for HPCI, RHR and Core Spray room cooler '

• Plans for monitoring pump motor coolers and seal coolers have not been establishe * A preventive maintenance request is required to' trigger periodic performance of EDG cooler monitorin Most of these items are identified in DAEC letter No. NG-93-4548 dated October 22, 1993, with pla.nned completion due dates between March and May 1994. The team found this proposed schedule to be acceptable. However, since there are some 20 action items in NG-93-4548 with completion dates between December 1993 and October 1994, the team was concerned that the heat exchanger program's '

full implementation might be further delayed. In response to this concern,

.

the licensee stated that completion of these action items would be closely I tracked and that additional resources would be applied where necessary to 1 preclude delays. The team found this response acceptabl ) Control Buildina Chiller Reliability l

The team determined that the check valves which isolate well water from ESW at the control building chiller inlet were not periodically tested in the reverse flow direction. The team also noted that alarm response procedures do not recognize potential chiller problems in extreme cold weather and do not ,

provice guidance to the operators as to alternatives or procedures to be followed, The notor-operated well water isolation valves are stroke time tested and are within the seismic category I boundary; therefore, credit can be taken for manual isolation should the well water check valve to the operating chiller f ail to close in an accident. However, since-the operator has no indication of this failure other than the direct consequences of operating chiller loss, system reliability could be improved by confirming closure of well water check valves during periodic condenser testing with ES Under accident conditions with very cold ESW (temperatures in the ic-30s and ;ower than ref rigerant temperatures), chiller performance a :

eliabi i depunds nn 3 three wa:. /31.+ 's capability to red _ra a

_ _ . _ ___ _ - _

-

- - . - ,

.

.. . . .

. .

A condenser ESW flow sufficiently to prevent the chiller from tripping on low suction pressure. In this case, chillers would be more reliable where well water remains available because well water temperature stays in the 50s year roun The licensee committed to change surveillance procedure No. STP48C001 to include positive confirmation of check valve operation. The licensee also stated that investigations into improving chiller reliability will continue, !

with ccnsideration given to providing the operating crews with enhanced '

guidance regarding the challenges presented by cold weather operation and options regarding operating the chillers with well water during these -

conditions. The team considered this response acceptabl .3 Diesel Coolant Cross Flow The team was concerned that the EDGs had a cooling system piping configuration ;

susceptible to cross flo Cross flow in the Fairbanks Horse (FM) 38TD8-1/8 opposed piston engines was i discovered in 1991 at ANO Unit 2 and reported by FM in a 10 CFR Part 2 Cross flow occurs during engine operation through piping installed to keep jacket water and air coolant systems warm while in stand-by. As a result of cross flow, some ' jacket water heat load is transferred to the air cooler, resulting in the air cooler exceeding 100% of its design basis heat loa r Cross flow at DAEC was evident in the results of recent GL 89-13 cooler testing as shown below:

.

Air Cooler Jacket Water Date Enoine Percent Load Percent Load ,

3-92 EDG-A 143% 54M 3-92 EDG-B 153% 4 15'

7-93 EDG-A 121% 49M 7-93 EDG-B 119% 43i

.

The plant was aware of this potential problem and had been monitoring engine performance accordingly. Currently, cooler monitoring results indicate the air cooler has sufficient margin to remove design basis heat including the contribution from jacket water through cross flow at minimum flow of approximately 400 gpm and maximum ESW temperature of 95 The team concluded that (1) DAEC is aware of cross flow and is monitoring performance accordingly and (2) cross flow does not appear to be having an adverse impact on engine performanc .4 Seisnic Qualification The interface between the seismic and non-seismic portions of ESW/RHRSW and '

wel' water return lines in the HPCI pump room was reviewed by the team for ade;uate system isolation. During this review. the licensee discovered that ths on-safe:v " elated 8"-JED-34 well water l- , which tied i" o t*: safety- ,

"

ed 24"- E -32 ESW/RHRSW return header. hac beer e>c'uded "om -~=

'

E

,

. . . _- . . . .

-

l

.

" Seismic Analyses for As-Built Safety-Related Piping Systems," IEB 79-14 review progra This discovery had two fundamental consequence Since the 8-inch pipe's analysis had not been reverified during the 79-14 as-built program, the current configuration's seismic adequacy was not strictly assured. Upon discovery, the licensee reviewed the existing analysis, performed in 1974, and conducted preliminary configurational walkdowns of l piping and supports. After correcting for an inaccurate stress l intensification factor at an unreinforced fabricated tee, they concluded that I the 8-inch pipe did not cause the 24-inch header to exceed any seismic operability criteria. The team concurred with this conclusio l However, from a broader perspective, the exclusion of this section of pipe !

potentially called into question the original 79-14 program scope's adequac l Although the licensee had performed a comprehensive reverification of all 79-14 calculations in the mid-1980s, this section of pipe evidently was overlooked because it had been excluded from the original program and there was no seismic calculation on file. Although the team considered this to be an isolated occurrence, pending final verification that the 8-inch pipe meets all applicable stress requirements and additional reviews regarding the

,

i original 79-14 program scope's adequacy, this was considered an Unresolved Item (331/93018-01) Operations i

The team reviewed plant operations to assess operator knowledge and the accuracy and completeness of procedures and training with regard to the SW ,

The team performed system walkdowns; reviewed procedures for normal, abnormal, '

and emergency conditions; assessed conduct of operations in the field and control room; and evaluated training manuals, lesson plans, and operator actions on simulated SWS malfunction .

The team conducted the inspection through discussions with coerations, engineering, and training personnel; evaluation of operating crews'

'

performance during a scenario designed around ESW and RHRSW system malfunctions; reviews of licensed and nonlicensed operator training materials, -

drawings, and operating instructions; and discussion of operational aspects of ,

the system with the licensee's staff.

.

The team determined the licensee was operating the SWS in an appropriate manne Although some weaknesses were identified, operating procedures, operator training program related to SWS, and operator knowledge of SWS equipment operations and procedures were considered effectiv The team considered the following to be strengths in the licensee's SWS training program: simulator use to evaluate SWS changes prior to irpiementation and incorporation of SWS changes in the training program and si Jiator for all levels of oferator ;

c e

_ _

_ __ . __ _ . . .. __ __ _ . . __

. .

t Operations Scenarios / Training The team identified several examples of incorrect modeling of components in the simulator. As a result, the team was concerned that simulator programming and simulator training may give operators a false sense of security relative to EDG capabilities to operate without coolin ! With current modeling, EDG continued operation does not appear to be assured beyond 2 to 3 minutes at full load and 10 to 15 minutes at no  !

load if ESW is los During a team observed plant simulator exercise scenario in which the ESW pump cooling a fully loaded EDG was tripped, the EDG continued to

.

i operate for approximately 20 minutes under reduced load. Based upon '

average lube oil heat rejection rates measured during GL 89-13 heat exchanger testing at DAEC, the team estimated EDG operation could not be assured beyond 2 to 3 minutes upon loss of cooling from full load, and 10 to 15 minutes on startup with no cooling and no load. The license ,

subsequently provided vendor documents which confirmed the team's estimate The licensee determined that the time that an EDG would be- able to run without ESW cooling was indeterminate. Further investigation by the licensee will be performed to determine an approximate time frame of EDG' '

availabilit Following this investigation, the simulator EDG moceling will be updated to more accurately reflect EDG availability following loss of ESW, and procedural revisions will be considered to provice the operating crew with the appropriate guidance. Additionally, the  !

licensee notified the operating crews relative to the indeterminate  ;

nature of EDG run time with a loss of ES The team considered this l response acceptabl A EDG frequency droop and EDG overspeed were incorrectly modele .

The licensee initiated DR-93-0065 to correct the simulator EDG overspeed -

trip setpoint. Additionally, the amount of speed droop anc the effect- '

of the mechanical governor on the inplant EDG will be investigatec for input into the simulator EDG modeling. Tne team considered this  ;

response acceptabl I Maintenance l

The team reviewed maintenance procedures, equip ent history, completed preventive and corrective maintenance packages, deviation reports, LERs  ;

nonconformances and quality assurance documentation for selected componerts to determine if the SWS components and ' piping were being adequately raintained and to detect any system that required more frecuent maintenance. The :eam also evaluated imiementation of GL 89-13 maintenance commitment .;

The team determined that SWS maintenance was acceptable and the 5'-~5 war functional. M e am observed that the licens. trended corditi:  !

of ?s j and salver *

wir Inservice lest (IST) Pr- m, but a t e': : p~: r i

!

l l

,

- - . - . - , , , . , . - . , , .

t

.. - .- - .. . .-

'

i i

. -)

had not been developed for SWS electrical components. The licensee's erosion and corrosion control program for the SWS did not include river water pipin The licensee's maintenance procedures were generally good; however, procedures I did not include provisions for inspecting for biofouling in the intake  !

structure or ESW/RHRSW pit or acceptance criteria for biofouling and corrosion l in heat exchanger .1 System Walkdown i

The team noted that SWS material condition was good and had improved since the previous SWS SSFI inspection of May 1990. No excess leakage was observed at i valves or pump seals. The licensee appeared to follow correct lubrication practices on valve stems, motors, and pump bearings. Few deficiency tags were ;

observed on the SWS equipment. The tags appeared to have not been in place for an excessively long tim .2 SWS Maintenance Observation l The team observed maintenance activities on valve No. TCV 5924 B, the three-way temperature control valve to the control building HVAC heat exchange The valve was rebuilt by plant maintenance personnel. The team noted that upon disassembly, .there was an accumulation of silt and mud on the upper control diaphragm's top that filled all available space on the diaphrag Valve trim was worn from use and/or abrasion and was replaced with a modified trim package. The valve was reassembled and tested prior to being returned to service. Review of training records revealed that craft personnel observed had received necessary training. Quality verification personnel were present !

and work authorization documentation was at the work locatio .3 Maintenance Procedures ,

The team reviewed electrical, mechanical and instrumentation maintenance and surveillance procedures for components within the SWS. The maintenance procedures for the SWS mechanical components included instructions for 1 inspecting and cleaning silt and sand from component i DAEC has not experienced problems with biofouling by either zebra riussels or :

asiatic clams; however, maintenance procedures for the intake strecture or the !

ESW/RHRSW pit did not provide instructions for identifying biofruling problems j such as moss, mussels, clams, grass, or snails. Guidance is caly provided for 1 the identification and removal of excessive sand and sil Procedure No GMP-

'

MECH-026, Revision 3, June 30,1993, " Heat Exchangers did not include inspec- !

tion guidance and acceptance criteria relative to corrosion or biofoulin l These procedural weaknesses had been identified by the licensee and the l procedures are to be revised to provide instructions to personnel performing the inspections and to include appropriate reporting guidance for hancling inspection result The team found this acceptable since both the ESW and RHR5W are recured during r- O pla ' cnenien. the RWS prps to 3 - W W ly treated < '117 W n

I l

!

-- --. . . , - - . _ -

-

.. - , .. . - . . - . - . . - - . . .

%

e

,

'

!

,

in the ESW/RHRSW pump house, and neither asiatic clams nor zebra mussels are i known to inhabit the Cedar River as ye I

! Surveillance and Testinq

'

The team reviewed and evaluated procedures pertaining to technical specification surveillances, inservice testing, heat exchanger heat transfer 4 capability, instrument calibrations, valve stroke time testing,. inservice test and equipment unavailability records, and periodic inspection program j implementation to detect biofouling flow blockage. Surveillance tests were i also witnessed and the air side of air-to-water heat exchangers were visually i examined by team members, i i

' Heat Exchanger Heat Transfer Testinq c

The team was concerned that the lack of valid baseline data for several heat exchangers did not provide a simple means to determine heat transfer degradation in the future, i

SWS heat exchangers' heat transfer performance ch:racteristics were determined i using Special Test Procedures (SpTP) 163A through 163J. Although these tests were performed duning the last two refueling outages, valid baseline data has not been obtained for several heat exchangers due to weaknesses in some test procedures. See Appendix B for specific comments regarding the licensee's actions in response to recommendations given in GL 89-1 The performance test for the control building chillers did not provide useful information because of incorrect testing methodology. The valve lineup specified for the test rc *1ted in measuring differential pressures that did not correlate to the servit water flow rate through the chiller. This inadequacy was recently recognized by the licensee and the test procedure had been revised, but had not yet been approve Similarly, the test results for several of the ECCS room coolers were inconclusive Decause the initial conditions specified in the procedure did not

,

provide sufficient heat loads to the heat exchangers. Minimal temperature changes durinc the test did not allow accurate extrapolations of room cooler capacitie ine team was not concerned with the current operation of room

oolers because of the apparent substantial margins for the room cooler However, the lack of valid baseline data does not provide a simple means to determine heat transfer degradation in the futur q Although the licensee had internally committec to improving specific aspects of their heat exchanger program based on their self-assessment of the SWs. the i team was concerned that full implementation might De delayed beyond their commitment dates. In response to this concern, the licensee stated that completion of :nese action items would be closely tracked and that additi: Sal researces woul be applied where necessary to preclude delay The tesm "ound this response icceptabl i h

!

.

. .

. . -

_-

,

I

. Unresolved Items Unresolved items are matters about which more information is required in order to ascertain whether they are acceptable items, violations or deviations. An unresolved item disclosed during the inspection is discussed in Section .0 Exit Meetina ,

,

The team conducted an exit meeting on November 5, 1993, at the Duane Arnold Energy Center to discuss the major areas reviewed during the inspection, the strengths and weaknesses observed, and the inspection results. Licensee representatives and NRC personnel in attendance at this exit meeting are documented in Appendix A of this report. The team also discussed the likely informational content of the inspection report with regard to documents reviewed by the team during the inspection. The licensee did not identify any documents or processes as proprietar i

e I

i

,

i l

l i

.- .

.

APPENDIX A [

!

PERSONNEL CONTACTED -

R. Murrell, Regulatory Comm. Specialist '

K. Peveler, Manager, Corporate Qulity Assurance '

K. Young, Manager, Nuclear Licensing D. Wilson, Plant Superintendent i

M. McDermott, Manager, Engineering  ;

T. Erger, System Engineer Group Leader l C. Bleau, System Engineer Supervisor J. Thorsteinson, APS Operations Support i P. Sabotta, ESW System Engineer  !

S. Swails, Manager, Nuclear Training P. Bessette, Supervisor, Regulatory Comm ,

"

M. Stewart, Mechanical Engineer, Safety Group B. Bernier, Mechanical Engineer, Supervisor

,

R. Anderson, Operations Supervisor A. Steen, Assistant Operations Supervisor  :

'

J. Kerr, Tech Support

!

5. Shangari, Engineering '

J. Kozman, Engineering D. Dobson, Mechanical Engineer J. Kinsey, Licensing Supervisor ,

i G. Van Middlesworth, APS - 0&M  ;

W. Simmons, Maintenance Specialist R. Anderson, Outage Project Manager  ;

A. Roderick, Supervisor, Test and Surveillance i D. Mienke, Outage Group B. Koltz, Group Leader, Quality Assurance

,

R. Baldyga, Maintenance Engineer Supervisor _

U. 5. Nuclear Resulatory Commission 1 J. Hopkins, Senior Resident Inspector .

C. Miller, Resident Inspection i

l

'l I

I

'

l I

. . . - - -

APPENDIX B Generic Letter 89-13 Action Items  !

In letters to the NRC dated January 29, 1990 and October 9,1990, the licensee provided commitments and status of programs, in place or to be implemented, to address the five actions requested in GL 89-13. In addition, the licensee issued two engineering department instructions related to GL 89-13; heat s exchanger performance and testing (EDI-2208.2 dated 8-19-92) and service water !

reliability program (EDI 2208.3 dated 8-19-92). Finally, an NRC SWS SSFI in early-1990 (report no. 50-331/900003DRS) and a licensee-initiated service ,

water operational performance inspection conducted by an independent contractor in July 1993 (Devonrue Report dated 8-27-93) evaluated status of GL 89-13 activitie ,

The team reviewed the above information and current status of relevant '

activities as described below. At DAEC, the generic term service water encompasses three separate systems: ESW, RHRSW, and RW ESW provides cooling to various essential systems such as emergency diesel generators, control room ,

chillers, ECCS pump room coolers, and ECCS pump motor coolers. RHRSW cools RHR heat exchangers, in both shutdown cooling and torus cccling modes. The RWS supplies water from the Cedar River intake structure to the ESW and RHRSW >

pump pits in the pump hous Biofouline Control and Surveillance Techniaues Action I of GL Ei-13 requested licensees to implement and sintain an ngoing program of sur.'e-llance and control techniques to significantly reduce the

!

incidence of flow blockage as a result of biofouling. Historically, biofouling has not been a problem at DAEC because (1) both the ESW an: RHRSW *

are secured during normal plant operation (2) the RWS pumps to a chemically ,

treated stilling basin in the ESW/RHRSW pump house and (3) neither asiatic clams nor zebra ussels are known to inhabit the Cedar Rive . In addi-ion, both the NRC's 'i30 SSFI and a 1993 sel f-initiated SSFI by in incepencent

.

contractor cor:1 ded that licensee activities were effecti'.e in prever:ing '

biofoulin l The team's res;e- focused on confirmation that licensee bicfouling prc; rams continue to be effective. The team found that heat excharger performance testing and preventive maintenance activities (open and inspect) indicate i continuing prcgrim effectiveness and that significant biofculing and  ;

microbiologically influenced corrosion problems have not been encounte-e l In ac:ition, t e :eam noted that the licensee's reply to c: cerns dur g the self-initiatec se vice water operational performance inspe:: ion inclu:ed a

-

commitment to :-e:are britten instructions for performing :i- irspect":ns and to e,aluate ir: :eed inspection techniques, with a action :_e da:e of rebruary 1, Isi". The :t - found this commitment acceptabl I

l

. .

-

-

.

APPENDIX B 2 I Monitoring Safety Related Heat Exchanger Performance Action II of GL 89-13 requested licensees to implement a test program to l periodically verify the heat transfer capability of safety related heat exchangers cooled by service wate The licensee uses a combination of testing and trending, including periodic open-and-inspect maintenance activities, to substantiate the heat transfer -

capability of safety related heat exchangers cooled by ESW and RHRSW. Program requirements are documented in two administrative procedures: EDI No. 2208.2, Revision 0, " Heat Exchanger Performance and Trending" and EDI No. 2208.3, Revision 0, " Service Water Reliability Program." The team determined that the licensee's program, for the most part, was being implemented effectively. A good deal of effort has been exerted in this area since the NRC's 1990 SSFI, although additional actions are required to fully achieve program objective The program's status, on a specific heat exchanger basis, is given belo Emergency Diesel Generator Coolers (IG-31 ::nd 1G-21)

EMP-lG031-HT was performed in July 1993, and a monthly STP monitors i temperature A cyclic preventive maintenance action request (PMAR) inspects tube side of heat exchanger and changes anodes. However, a PMAR is r.eeded to trigger performance of EMP-lG031-HT. Testing is performed at a flow rate below the minimum stated in the FSAR. Therefore, this testing demonstrates the availability of cooling margin since under normal operating or accident conditions, higher flow rates would be provide RHR Heat Exchangers (IE201A and 1E201BJ

!

EMP-lE201-HT was performed in draft form in March 9 Heat exchangers (tube side) wert last cleaned in 1990. The next cleaning is scheduled for May 1996 l for "A" and May 1998 for "B". Control Building Chillers (1VCH001 A and IVCH001B1

EMP-1VCH001-HT was draf ted in July 1993 but has never been performed. All

, condenser tubes have been replaced since 1990. EMP-IVCH001-HT needs to be formally reviewed, approved and performed. A PMAR is being considered to l clean / inspect the condenser tubes on an 18 month frequency. A frequency needs I to be established and adopted. Accident heat loads are limited to 75 hp both by chiller controls and decreasing control building loads under accicent conditions. Hence, successful chiller operation at normal loading (rear 200 hp). particularly in summer months, provides additional evidence of cooling water ef fectivenes i l

l l

l

I 1 *

l l

i l

APPENDIX B 3 *

l

,

' RHR and Core Spray Room Coolers (IVAC001 and IVAC0121 The last heat transfer testing was during cleaning PMARs in Summer 199 There was no detectable change in heat transfer since the last cleaning; however, low heat loads contributed to poor results. In summer 1993, room temperature was monitored with one RHR pump in the torus cooling mode. The cooler operated less than 25% of the time. IVAC012 tube temperatures were recorded and small deviations in temperature were observed. Monitoring tube temperatures does not appear to be effective; however, ECCS room coolers appear to have substantial margin beyond accident cooling requirement HPCI Rcom Coolers (IVAC0J4A & B)

.

The last heat transfer testing was during cleaning PMARs in summer 199 There was no detectable change in heat transfer since cleaning. Low heat loads contributed to poor results; however, ECCS room coolers appear to have ;

substantial margin beyond accident cooling requirement j RCIC Room Coolers (IVAC015A &_B1

!

Tne last heat transfer was testing during cleaning PMARs in summer 199 Inere was no detectable change in heat transfer since cleaning, but low heat loads contributed to poor results. The B-cooler was not cleaned based on the '

heat transfer results. EMP-lVAC015-HT was performed on the B-cooler in April ,

of 1993 under design heat load conditions. The test results indicated greater inan design heat transfe The test will be repeated this winter. ECCS room ,

coolers appear to have substantial margin beyond accident cooling requirement [ Core Spr.ay_ Pump Motor Coolers (IP_211 A & Bjand RHRSW P_u_mp Motor Coolers

_

LIP 022A, B,_C, and l Searing temperatures are not formally monitored. Flow was last verified in 1992 outage. The licensee needs to formalize bearing monitoring and develop a E5W flow verification tes >

>

i Tne team noted that in the licensee's responses to the self-initiated service 3 water operational performance inspection the licensee made certain commitments relative to completing outstanding activities associated with heat exchanger !

performance monitoring, and heat exchanger inspection and maintenance. The licensee established May 1, 1994, as the due date to correct verification test '

inadequacies, May 1, 1994, for baseline testing and enhancements to heat i exchanger monitoring, and March 1, 1994, to resolve concerns regarding heat exchanger inspection acceptance criteria. The team found these target dates  ;

acceptable, provided that they are firm dates anc not allowed to slip beyond the '

re frames indicate ;

'

.

B l

,

. _ _ - _ _

,-

. _ -- .

. .

f

.

.

APPENDIX B 4 II Routine Inspection and Maintenance Action III of GL 89-13 requested licensees to implement a routine inspection and

'

maintenance program for open-cycle service water piping and components. This program should ensure corrosion, erosion, protective coating failure, silting, and biofouling cannot degrade performance of safety related systems supplied by service wate As noted in paragraph II above, heat exchangers are planned for periodic opening and inspection in conjunction with engineering department instructions. While this routine maintenance may be revised and adjusted as result of monitoring, testing, and trending, the team found the following PMARs currently in effect:

C_omponent PMAR N Job Description RHR HXs MM-4Rl(2)-INS Clean coils and inspect RHR/CS Rm Coolers MM-2Y2-REP Clean coils on water side HPCI/RCIC Rm Coolers MM-2Y2-REP Clean coils on water side EDG Cooler MM-IRO-INS Complete mechanical inspection In addition to the above mechanical inspections, the DAEC pipe-wall thinning surveillance program, initiated to monitor status of steam and high pressure piping, is being extended to include portions of service water piping. In letter NG-93-4548 October 22, 1993, the licensee cormitted to prepare criteria for selecting service water ultra-sonic monitoring points and to incorporate requirements into appropriate control procedures by June 30, 1994 The team found this commitment acceptabl Since the SWSs are low pressure systems this monitoring will complement the present inspection and testing programs to preclude premature failures as a >

result of corrosion, erosion, silting, or related causes. To this end, the team found the total service water inspection and maintenance program at DAEC to be acceptable, subject to the comments of paragraph III above on completion of outstanding items from the self-initiated service water operational performance inspeccio I Design Function Verification and Single Failure Analysis Ac'. ion IV of GL 89-13 requested licensees to confirm that service water will perform its intended function in accordance witn the licensed basis for the pian This confirmation should include a review of the ability to perform '

requircd safety functions in the event of f ailure of a single active componen The team reviewed system drawings, conducted plant wa l k-d own s , and reviewed cesign calculations with a view toward system functionality and potential single

• :iure vulnerabilities. Many design calculati:ns had Deen performed since the NRC's 1990 SSFI, hence the team paid particula attention to these document ' ~ neral casen , Se team spot-checked the re" .' of inese calc. Mions uyir$

~utive techn cm or methocolog These * .its w cons;'~c tly

,

- .__ - --. . -- . - . -- - - -.

,

. .

.

APPENDIX B 5 *

i

!

determined to be valid. The team also evaluated several potential single failure vulnerabilities and determined that system safety functions were not precluded i by single failures. In addition, the team noted that both the 1990 NRC SSFI and the 1993 self-initiated SSFI arrived at similar conclusions relative to potential single failure *

The team noted the SWS design provides high safety function reliability based upon the following: In most instances there is substantial flow margin. For example, only 1 of 4 RWS pumps needs to function to provide all required safety coolin *

Also, each ESW pump is capable of approximately 1200 gpm while only minimum flow is achieved by approximately 750 gp !

! RWS and RHRSW are single flow path systems requiring basically no flow balanc Recent flow balances have shown all ESW flow paths receive minimum fl o Only one valve in the ESW system is in a throttled position, the EDG cooler outlet valv The control ' building chillers are normally cooled by the relatively clean i well water system. ESW automatically replaces well water to the chiller '

anytime the ESW pump starts because ESW is at a higher pressure than well wate ! RWS is in operation under normal and accident conditions and RHRSW is always manually initiate ; Control building chillers carry only a restricted air conditioning load l (75 hp) under accident conditions. Hence, they constantly demonstrate additional capability during normal operatio I The team concluded the DAEC service water systems (ESW, RHRSW, and RWS) are -

l capable of performing intended safety functions under postulated conditions l including the most limiting single active failure j Training

,

Action V of GL 89-13 requested licensees confirm that maintenance practices, operating and emergency procedures, and training that involves service water be adequate to assure safety related equipment cooled by service water function as intended and that operators of this equipment perform effectivel Based on the team's review of riaintenance practices, operating and' emercency procedures, training documentation, and crew performance during simulator training exercises, the team concluded that Action V was appropriately acceoplishe ;